After running a Source Subscription to batch update specific fields, such as specialties and focus areas, some records are not getting updated, even though the subscription job completes without any errors.
This behavior is working as designed and caused by a misconfiguration of the Source Rankings. The System used in the Source Subscription has a lower source rank than the one used to originally load those values.
For example, the System which ran to perform a batch load System B has a ranking of 3 but the System which was originally used for loading these values System A has a ranking of 2.
Network Online Help: Source rankings